Functional characterization of a wheat NHX antiporter gene TaNHX2 that encodes a K(+)/H(+) exchanger.
Functional characterization of a wheat NHX antiporter gene TaNHX2 that encodes a K(+)/H(+) exchanger.
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DOI：
10.1371/journal.pone.0078098
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发表时间：
2013
期刊：
影响因子：
3.7
通讯作者：
Jiang X
中科院分区：
文献类型：
--
作者：
Xu Y;Zhou Y;Hong S;Xia Z;Cui D;Guo J;Xu H;Jiang X
研究了小麦NHx逆向转运蛋白TaNHX2在拟南芥原生质体中的亚细胞定位，并利用酿酒酵母作为异源表达系统对其功能进行了评价。TaNHX2-GFP融合蛋白在拟南芥细胞中的荧光图谱表明，TaNHX2定位于内膜。TaNHX2与拟南芥NHx钠交换器有显著的序列同源性，在根和叶中含量丰富，受盐或脱水处理诱导。Western印迹分析表明，TaNHX2在转基因酵母细胞中得到了表达。表达的TaNHX2蛋白通过增加酵母突变株在盐胁迫下的K+含量来抑制其对盐的敏感性。TaNHX2还提高了菌株对钾胁迫的耐受性。然而，TaNHX2的表达并不影响转基因细胞中的钠浓度。液泡膜蛋白的Western印迹分析表明，TaNHX2蛋白定位于转基因酵母细胞的液泡膜上。与空载体转化的对照相比，转基因酵母细胞的液泡膜K+/H+交换活性增强，但Na+/H+交换活性很低，当反应介质中Na+浓度低于37.5 mM时，未检测到Na+/H+交换。我们的数据表明，TaNHX2是一种内膜结合蛋白，可能主要作为K+/H+逆向转运蛋白发挥作用，在正常情况下参与细胞pH调节和钾营养。在盐分条件下，该蛋白通过细胞内钾的区域化来调节细胞的pH和K+动态平衡，从而介导对盐胁迫的抗性。
The subcellular localization of a wheat NHX antiporter, TaNHX2, was studied in Arabidopsis protoplasts, and its function was evaluated using Saccharomyces cerevisiae as a heterologous expression system. Fluorescence patterns of TaNHX2-GFP fusion protein in Arabidopsis cells indicated that TaNHX2 localized at endomembranes. TaNHX2 has significant sequence homology to NHX sodium exchangers from Arabidopsis, is abundant in roots and leaves and is induced by salt or dehydration treatments. Western blot analysis showed that TaNHX2 could be expressed in transgenic yeast cells. Expressed TaNHX2 protein suppressed the salt sensitivity of a yeast mutant strain by increasing its K+ content when exposed to salt stress. TaNHX2 also increased the tolerance of the strain to potassium stress. However, the expression of TaNHX2 did not affect the sodium concentration in transgenic cells. Western blot analysis for tonoplast proteins indicated that the TaNHX2 protein localized at the tonoplast of transgenic yeast cells. The tonoplast vesicles from transgenic yeast cells displayed enhanced K+/H+ exchange activity but very little Na+/H+ exchange compared with controls transformed with the empty vector; Na+/H+ exchange was not detected with concentrations of less than 37.5 mM Na+ in the reaction medium. Our data suggest that TaNHX2 is a endomembrane-bound protein and may primarily function as a K+/H+ antiporter, which is involved in cellular pH regulation and potassium nutrition under normal conditions. Under saline conditions, the protein mediates resistance to salt stress through the intracellular compartmentalization of potassium to regulate cellular pH and K+ homeostasis.
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影响因子：
3.5
作者：
Quintero, FJ;Blatt, MR;Pardo, JM
通讯作者：
Pardo, JM
DOI：
10.1073/pnas.122224699
发表时间：
2002-06-11
影响因子：
11.1
作者：
Qiu, QS;Guo, Y;Zhu, JK
通讯作者：
Zhu, JK
影响因子：
7.4
作者：
Martinez-Atienza, Juliana;Jiang, Xingyu;Quintero, Francisco J.
通讯作者：
Quintero, Francisco J.
影响因子：
11.6
作者：
Bassil, Elias;Ohto, Masa-aki;Blumwald, Eduardo
通讯作者：
Blumwald, Eduardo
影响因子：
4.1
作者：
Darley, CP;van Wuytswinkel, OCM;de Boer, AH
通讯作者：
de Boer, AH